Fuel supply system



Dec. 16, 1958 M, C, BARTZ 2,864,354

FUEL SUPPLY SYSTEM Filed OCL. 25. 1956 ze "E ITEZ @Mm-J A WOP/VFY United States Patent O FUEL sUrPLY SYSTEM Melvin C. Bal-tz, South Bend, Ind., assignor to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Application October 25, 1956, Serial No. 618,365

11 Claims. `(Cl. 123119) The present invention relates to a fuel supply system for an engine wherein fuel is supplied to a fuel valve or valves at a controlled pressure or pressures and the time duration of valve opening is controlled as a function of an engine operating condition such as speed, engine temperature, ambient pressure relative humidity or induction passage pressure.

A fuel system of this general type is disclosed and claimed in .copending U. S. application Serial No. 567,688 filed February 24, 1956, now abandonedfiled in the names of Robert W. Sutton, Stephen G. Woodward and Curtis A. Hartman and assigned to the assignee of the present invention.

It is an object of my invention to provide a simple, reliable, easily manufacturable control for a fuel supply system.

It is a further object of my invention to provide a relatively stable control for a fuel supply system which `is substantially unaffected by vibration, shock and temperatures normally encountered in engine operation.

lt is a still further-object of my invention to provide a control for a fuel supply system which is compact and light weight.

Other objects and advantages of my invention will be through a switch to a plurality of parallel connected variable potentiometers respectively designated R1, R2, R3 and R4. Potentiometers R1, R2, R3 and R4 are collectively designated Rt. The output from Rt is connected to ground or reference potential through a summing resistor Rs. The output of R, is also connected to a primary inductor 12 intermediate the ends thereof. The primary inductor 12 is wound about a high retentivity core 14 which has a substantially square loop hysteresis curve as shown in Figure 2. A second inductor 16 is also WoundY about core 14 and inductively coupled to the primary.

winding 12. One side of the secondary inductor is connected to ground or a reference potential and the other side is connected to a plurality of solenoids 18 respectively located in electrically actuable fuel control members or valves 19. The individual solenoids are respectively designated 18a', b, c, a', e, f, g and h, the diagram illustrating the arrangement for an 8-cylinder engine. It is to be understood that my invention may be used with various engines having various types of combustion chambers and that the proportion of solenoids to com bustion chambers may be varied as desired.

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The solenoids 18 are respectively connected to seg# ments 20a, b, c, d, e, f, g, and h mounted in a distributorswitch unit 22 by appropriate conductors (not shown). A wiper arm 24 is mounted in unit 22 for rotation as a function of engine speed so as to successively engage the contacts 20.` The arm 24 is connected to ground or a reference potential. Also located in unit 22 are a plurality of segmental contacts 26 which are alternatively connected to opposite ends of the primary inductor 12. The portions of the primary inductor between the Rt center' tap and the ends thereof are respectively designated 12E,j and 12b. Wiper arm 24 is adapted to successively engage the segmental contacts 26 whereby the portions 12a and" 12b of the primary inductor are alternatively connected to ground or reference potential.

The voltage-ux-time relationship in core 14 is gven by the following equation:

s=Saturation ux The total flux therefore from negative to positive saturation is equal to 2s and is equal to a constant times a voltage-time product. Thus the length of time for. the' ilux to change from negative to positive saturation in the core is inversely proportional to the voltage applied. The current induced in secondary inductor -16 is equal to the` Therefore, by controlling the voltage across summing resistor Rs a controlled time duration of current flow in the secondary inductor 16 is obtained. The voltage across Rs is controlled by the potentiometers Rt.

In a preferred embodiment R1 is varied in response to changes in engine temperature, R2 in response to changes in ambient temperature, R3 in response to changes in induction passage pressure, and R4 in response to changes in ambient air pressure. In different installations Rt may be varied by omission of certain of the potentiometers. R1, R2, R3 or R4 and in some cases additional or sub: s titute potentiometers may be utilized which are respon sive to other engine operating conditions such as oil pressure, exhaust temperature, combustion chamber temperature and exhaust pressure, etc.

As shown in Figure 2 the high retentivity core 14 pro-'- duces a substantially square loop hysteresis curve. This* produces a substantial improvement in the-operation of' my device since when the arm 24 breaks contact with azi'. segment 26 and the current in the appropriate portion of-f; f primary inductor 12 goes to zero the flux does not change and therefore there is no surge of back E. M. F. in the* inductor.

As shown in Figure 3, the fuel control memberoft valve 19 is mounted in the induction passage 30 of ainternal combustion engine 32 having a combustion chamber 34. Fuel from the supply tank 36 is placed?- under pressure by pump 38 and delivered to the valve 19` via conduit 40. Fuel supplied tovalve 19 -in excess? of the amount injected into the engine is returned to the supply tank via conduit 42.

In operation the circuit is energized by closing switch 10, which may be the conventional ignition switch, whereby the source of power E is connected to potentiometers Rt. The voltage drop across Rt is controlled by any desired combination of potentiometers` R1, R2, R3 and R4 which are controlled as a function of engine operating conditions. The wiper arm engaging segments 26 causes current to ow rst in portion 12 and then 12b of the primary inductor 12 whereby the core is alternatively driven into positive and negative saturation. The time for the core to be driven into saturation is controlled by the voltage applied to the primary inductor. A current is induced in the secondary -16 for a time equal to the time for the flux in core 14 to change Vfrom positive to negative saturation. Thus a current is supplied to solenoids 18 for a controlled time duration. Wiper arm 24 successively connects the appropriate solenoids to ground as a function of engine speed and in accordance with the firing order of the cylinders if the fuel supply system should be used with an engine of the internal combustion cylinder type.

There are no tubes or sensitive elements in the control and the construction of the inductors and potentiometers is such to provide extreme reliability to the control 'which is substantially unaffected by shock, vibration or tempera.` ture which may be normally encountered in engine operation. There are relatively few parts to my control and they may be compactly assembled in a relatively light weight package.

While only one embodiment of my invention has been described it will be readily apparent to those skilled in the art that various changes and arrangements can be made to obtain the objects of the invention without departing from the spirit thereof.

I claim:

1. A control for a fuel system having an electrically actuable fuel valve and a lsource of power, a pair of coupled inductors, means for connecting said source to one of said inductors, means for controlling the time duration of current flow in the other of said inductors,

and means for connecting said other conductor to said valve.

2. A fuel supply system for an engine having an induction passage and an electrically actuable fuel valve and a source of power, a pair of coupled inductors, means for connecting said source to one of said inductors, means responsive to induction passage pressure for varying the time duration of current flow in the other of -said inductors, and means for connecting said other inductor to said valve.

3. A fuel supply system for an engine having an electrically actuable fuel valve and a source of power, a pair of coupled inductors, means for connecting said source to one of said inductors, means responsive to engine temperature for controlling the time duration of current ow in the other of said inductors, and means for connecting said other inductors to said valve.

4. A fuel supply system for an engine having an electrically actuable fuel valve and a source of power, a pair of coupled inductors, means for connecting said source to one of said inductors, means responsive to ambient temperature for controlling the time duration of current ow in the other of said inductors, and means for connecting said other inductor to said valve.

5. A fuel supply system for an engine having electrically actuable fuel valve and a source of power, a pair of coupled inductors, means for connecting said source to one of said inductors, means responsive to ambient air pressure for controlling the time duration of current ow in the other of said inductors, means for connecting said other inductor to said valve.

6. A fuel supply system for an engine having an electrically actuable fuel valve and a source of power, a pair of coupled inductors,means for connecting said source to one of said inductors, means responsive to an engine operating condition for controlling the time duration of current ow in the other of said inductors, and means for connecting said other inductor to said valve.

7. A fuel supply system for an engine having an electrically actuable fuel control member, a source of electromotive force, a saturable inductor, means for connecting said source to said inductor, means responsive to an engine operating condition for varying the magnitude of the electromotive force above a magnitude sufficient to saturate said inductor, a secondary inductor coupled to said saturable inductor, and means for connecting said secondary inductor to said member.

8. In a fuel supply 'system having an electrically actuable fuel control member, a core, an inductor wound about said core, a source of power, means connecting said source to said inductor Vintermediate the ends thereof, means for alternatively connecting the ends of said conductor to a reference potential, a secondary inductor coupled to said first mentioned inductor, and means for connecting said secondary inductor to said member.

9. A control for a fuel supply system for an engine having an induction passage and a solenoid actuated fuel valve, a core, a primary inductor coiled about said core, a voltage source, meansconnecting said source to said inductor intermediate the ends thereof, means responsive to engine speed for alternatively connecting the ends of said 'inductor to ground, a secondary inductor coupled to said primary inductor, means responsive to an engine operating condition such as ambient temperature, engine temperature, ambient pressure or induction passage pressure for varying the voltage to said primary inductor to vary the time duration of current flow in said secondary inductor, and means connecting said secondary inductor to said solenoid.

10. A control for a fuel supply system for an engine having an induction passage and a plurality of solenoid actuated fuel valves, a core, a primary inductor coiled about said core, a voltage source, means connecting said source to said inductor intermediate the ends thereof, means responsive of engine speed for alternatively connecting the ends of said inductor to ground, a secondary inductor coupled to said primary inductor, means responsive to an engine operating condition such as ambientv temperature, engine temperature, ambient pressure or induction passage pressure 4for varying the voltage to said primary inductor to vary the time duration of current How in said secondary inductor, and means responsive to engine speed for successively connecting said secondary inductor to said solenoids.

l1. A control for a plurality of fuel valves in a fuel supply system comprising: a high retentivity core, a primary winding in said core, a source of voltage, means connecting said source to said winding intermediate the ends thereof, means for varying the voltage in excess of an amount sufficient to saturate said core, means responsive to engine speed for alternatively connecting the ends of said winding to ground whereby said core is alternatively, positively and negatively saturated, a secondary winding inductively coupled to said primary winding, a magnetic means for actuating each of said valves, and means responsive to engine speed for successively connecting said secondary winding to said magnetic means.

References Cited in the file of this patent UNITED STATES PATENTS 2,468,917 Booth May 3, 1949 FOREIGN PATENTS 198,796 Switzerland Oct. 1, 1938 971,274 France July 5, 1950 

